The Field of the Invention
This invention relates to vernier measuring devices, and more particularly to that class of apparatus utilizing electronic components for the measurements of angular rotation and linear measurements, employed in compasses, resolvers, position and location sensors and encoders.
In particular, this invention relates to an electrical measuring device in which the change in the physical condition of a sensing apparatus is utilized to measured displacements or angular positions. Heretofore, mechanical devices, such as micrometers, calipers, linear scales, amongst others, have been provided with vernier scale elements which require the user to manually and serially perform the operation of determining a rough measurement, and then by consulting the vernier scales, arriving at a more accurate measurement. Invariably, one portion of the vernier scale was movable and positioned adjacent another portion a readable scale, requiring the user to compare their relative positions when making the vernier reading. Such arrangements have been, and are, to a great extent, limited in their effectiveness by the small size of the moving vernier scale and its inherent mechanical accuracy.
It is an object of the present invention to provide a simple arrangement which is extremely reliable and free from extraneous input, providing an error-free measuring device, which does not employ a moving vernier scale element that requires user visualization.
A further object of the present invention is to provide an apparatus which is capable of measuring angular positions or linear displacements, providing an indication thereof to either an electronic visual display, other control devices, or computers, with or without associated visual displays.
Another object of the present invention is to provide an apparatus for the convenience of the user which does not require any visualization of the measurement apparatus, save a remote display portion, if one is employed.
Still another object of the present invention is to provide an apparatus which does not employ moving electrical contacts, by an in between its stationary and movable elements, thereby eliminating wear, friction, and error.
A still further object of the present invention is to provide an apparatus which is insensitive to long term changes in temperature, supply voltage, resistance, and the like.
Yet another object of the present invention is to provide a measuring device which performs its measurements repeatedly, over short periods of time, so as to eliminate drift considerations and the introduction or error thereby.
Yet another object of the present invention is to provide a measurement device which utilizes solid state circuitry for switching purposes thereby eliminating noise, power loss, error, delay, failures, and bulk and weight.
A still further object of the present invention is to provide an electronic vernier measurement device which utilizes a minimum number of leads from its sensor apparatus to obtain resolutions to a high order of magnitude.
Still another object of the present invention is to provide a measurement device capable of utilizing coarser markings than present optical encoders whilts producing an equivalent or higher resolution, thereby reducing cost .